1. FIELD OF THE INVENTION
This invention relates to the attachment at a precise position of a first member to a second member which is not as precisely positioned as the first member, and provides a method of and apparatus for locating the position of the first member and for reforming the second member by a variable magnitude depending on the actual position of the second member relative to a predetermined position. The invention relates, in particular, to the precise attachment of an outer body panel member of an automotive vehicle to an imprecisely located element of an inner body frame structure, particularly an inner body frame structure in which only one surface is accessible.
2. DESCRIPTION OF THE PRIOR ART
U.S. Pat. No. 4,438,971 to Zaydel et al, describes a method and an apparatus for attaching, at a precise location, a plastic automotive body panel to a relatively imprecisely located element of an inner body frame structure. According to the teachings of this patent, plastic filled metal attachment blocks or pads are welded at selected locations to the inner body panel structure. The inner body panel structure is then positioned within a locating and machining fixture and each of the plastic filled attachment blocks is milled to a precise location, the distance between the inner body frame structure and the milled face of the plastic filled attachment block varying with the position of the inner body frame structure. The plastic outer body panel member is then attached to the milled face of the plastic filled attachment block, after drilling a hole in the plastic filled attachment block to receive a threaded fastener or a fastener attached to the inside of the plastic outer body panel member. By this method and apparatus, each such plastic outer body panel member is mounted at a precisely determined location and in precise surface alignment with each adjacent plastic panel.
The method and apparatus of the aforesaid U.S. Pat. No. 4,438,971 does lead to precision in the locating of plastic outer panels to a relatively imprecisely positioned automotive inner body frame structure, but it requires the initial attachment of the plastic filled attachment block to the inner body frame structure, a factor which adds to the material and processing costs of producing an automotive body in this manner, and a welding operation that is needed to attach the plastic filled metal attachment block is noisy and dirty. Additionally, the subsequent milling of the plastic filled attachment blocks generates scrap having a composition containing a mixture of metal and a plastic filler material which, for the disposition of such scrap in an environmentally acceptable manner, involves additional expense. In any case, milling of the plastic filled attachment blocks generates dust corresponding, mainly, to the composition of the plastic filler which is objectionable on environmental and work place health and safety grounds, unless strict precautions are followed in performing the milling and drilling of the plastic filled attachment blocks.
It is also known in the prior art that a relatively imprecisely located automotive inner body frame element can be built up to provide for the attachment thereto of an outer body element at a more precisely determined location by attaching one or more metal shims to the surface of the inner body frame element to which the outer body panel element is to be attached. The number of such shims to be attached is based upon the original position of the inner body frame element. However, this is a time consuming and expensive procedure, as each shim must be individually sized and positioned and the attachment of such shims adds to the weight of the vehicle, an undesirable feature since it detracts from fuel economy. An example of a shim system which addresses these problems is U.S. Pat. No. 4,437,784 to Peterson which discloses a collapsible metal shim member that allows a surface of the shim to be spaced a predetermined distance from a support member to which it is attached. These shims must be preattached to the frame and their collapsibility limits their inherent strength and stability.
It is additionally known in the prior art to provide a shank having a tapered tip which is able to pierce a sheet material, thereby producing flared ridges of the sheet material around the periphery of the hole thereby produced. U.S. Pat. No. 4,068,554 to Hirabayashi is an example of such a device. The device is composed of a shank and a tip, wherein the tip is further composed of a point and a base portion. The point has a pair of pyramidally shaped, regularly polygonal cross-sections and has a certain number of edges extending divergently at an obtuse angle from the base portion. The base portion has a smaller number of rounded ridges relative to the number of edges in the point. Each of the rounded ridges has a curved outer surface, becoming wider as they approach the shank. In operation, the point of the device pierces the sheet material, and as the device further penetrates into the sheet material, the sheet material is caused to flare on the opposite surface from that of entry of the device.
Devices such as these are used to provide a flaring of the sheet material, as well as a hole therethrough, so that the threads of a threaded fastener will have an adequate anchorage in relation to the sheet material. However, these devices fail to adjust for variations in the precise position of the sheet material, as all that is provided thereby is a hole for fastening a threaded fastener thereinto without any accommodation for variation in surface position of the sheet material. Thus, while such devices provide for reliable and inexpensive attachment between elements, there is no provision for precisely adjusting the relative position between the elements.
An apparatus and method for reforming the surface of an inner body frame member to provide precise location of the attachment point of an outer body panel thereto is described in my co-pending patent application, Ser. No. 810,045, filed Sept. 17, 1985 now U.S. Pat. No. 4,760,633. Therein is disclosed an apparatus including a movable ram, floating support attachments and fixed anvils. The movable ram is located on one side of the inner body frame member, while the fixed anvils are located on the other side thereof. The movable ram is movable toward and away from the aforesaid side of the inner body frame element. The movable ram has associated pad forming blocks which contact the surfaces of the inner body frame members on the opposite side of the fixed anvils. After the floating support attachments have been brought into contact with the surface of the inner body frame member that is to be reformed and have been locked in position, the movable ram is actuated to move toward the inner body frame member and reform the portions thereof that are trapped between the fixed anvils and the pad forming blocks. Thus, the inner body frame member will be provided with one or more pads, the outside surface of each of which corresponds in position to the fixed position of the fixed anvil against which it is formed, regardless of the original position of the inner body frame member from which it is formed. The depth of each of such pads varies, therefore, according to the difference between the fixed position of its outer surface and the original position of the portion of the outer surface of the inner body frame member from which it is formed. Each of the aforesaid pads is ready for the attachment of an outer body panel member thereto without any further machining or any other processing being required to establish its fixed location. The only additional processing normally required is the lancing, punching or piercing of an aperture in such pad to receive a fastener for the fastening of the outer panel element thereto which, if desired, is most conveniently performed during the forming of the pad by a tool which reciprocates within the fixed anvils. While the aforesaid method and apparatus is very satisfactory for inner body frame structures having surfaces accessible on both sides, it is not suitable for inner body frame structures having tubular or channel structures in which the opposite side surface is inaccessible.
Accordingly, there remains in the art the need to provide a method and apparatus for reforming a first element so as to precisely position a second element thereto, where the first element has only one side which is accessible, and further where the reforming of the first element is inexpensive, environmentally safe and simple to accomplish.